4-Inch Low-Voltage Steel Mounting Bracket, Class 2 Applications
https://nsiindustries.com/product/4-inch-low-voltage-steel-mounting-bracket-class-2-applications/
This Bridgeport Low-Voltage Mounting Bracket eliminates the need an outlet box. Designed for old work and mounting standard Class 2 low-voltage outlets or plates. Built to the high standards of Bridgeport for professional users.